; Select audio/midi flags here according to platform ; Audio out Audio in No messages -odac -iadc -d ;;;RT audio I/O ; For Non-realtime ouput leave only the line below: ; -o biquad.wav -W ;;; for file output any platform ; Initialize the global variables. sr = 44100 kr = 4410 ksmps = 10 nchnls = 2 ; Instrument #1. instr 1 ; Get the values from the score. idur = p3 iamp = p4 icps = cpspch(p5) kfco = p6 krez = p7 ; Calculate the biquadratic filter's coefficients kfcon = 2*3.14159265*kfco/sr kalpha = 1-2*krez*cos(kfcon)*cos(kfcon)+krez*krez*cos(2*kfcon) kbeta = krez*krez*sin(2*kfcon)-2*krez*cos(kfcon)*sin(kfcon) kgama = 1+cos(kfcon) km1 = kalpha*kgama+kbeta*sin(kfcon) km2 = kalpha*kgama-kbeta*sin(kfcon) kden = sqrt(km1*km1+km2*km2) kb0 = 1.5*(kalpha*kalpha+kbeta*kbeta)/kden kb1 = kb0 kb2 = 0 ka0 = 1 ka1 = -2*krez*cos(kfcon) ka2 = krez*krez ; Generate an input signal. axn vco 1, icps, 1 ; Filter the input signal. ayn biquad axn, kb0, kb1, kb2, ka0, ka1, ka2 outs ayn*iamp/2, ayn*iamp/2 endin ; Table #1, a sine wave. f 1 0 16384 10 1 ; Sta Dur Amp Pitch Fco Rez i 1 0.0 1.0 20000 6.00 1000 .8 i 1 1.0 1.0 20000 6.03 2000 .95 e